[RESOLVED] Read randon line from txt with CFv3.5

[herpez]

Hi. I'm making a program for windows mobile 6 (uses .NET compact framework 3.5),

The goal for the problem is to read one random line from a txt file and display it.

I found some examples but most of all use File.ReadAllLines witch is not available in CFv3.5

As for now, i can't do it, and i tried lots of ways.

Thanks

[jmcilhinney]

Please post your Mobile questions in the Mobile forum. I've asked the mods to move this thread.

Create a StreamReader, call ReadToEnd to get the entire contents into a String, then call Split on that String to split on the line breaks. That will give you a String array, just like File.ReadAllLines, so everything from there should be the same.

[si_the_geek]

Thread moved to '.Net \ Mobile Development' forum

(thanks for letting us know jmcilhinney )

[herpez]

Thanks jmcilhinney and thanks the mods for moving it.

My apologies for post in the wrong section.

I will code and if new doubts come, i will update.

Thanks

[herpez]

Hi. I have successfull coded. However in the textbox outupt it shoes a blank line before the words.

The code:

 Dim TextFile() As String
        Dim dir As String = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase)
        Dim FILE_NAME As String = (dir + "\\fernandopessoa.txt")
        Dim RandomNumber As Integer
        Dim RandomClass As New Random()
        Dim var As String

        If File.Exists(FILE_NAME) Then
            Dim objReader As New System.IO.StreamReader(FILE_NAME)
            Dim s As String = objReader.ReadToEnd
            Dim numero As String
            TextFile = s.Split(vbNewLine)
            numero = (TextFile.Length - 1)
            RandomNumber = RandomClass.Next(0, numero)

            var = TextFile(RandomNumber)
            Label1.Text = var
            objReader.Close()
            objReader.Dispose()
        End If

The output
first line of the txt is good, for example:
"Hello world"

However, ALL the others have first one blank line, like this:
"
Hello world2"

What is wrong?

Thanks

[jmcilhinney]

The problem is the fact that a line break is actually two characters (CR LF) and the overload of Split that you're using, which is the only one supported on the CF, will only split on single characters. I think that the best answer is to split on just CR or just LF, then loop though the resulting array and use TrimStart to trim the LF from the beginning of each element or TrimEnd to trim the CR from the end of each element.

Also, you should turn Option Strict On, which would have caused a compilation error in your code to notify you that there was an issue, rather than compiling and running but producing incorrect results.

[herpez]

Hi.

EDITED because i'm further in codding

I have added Option Strict On and accepted suggestion about how to recode correctly.
I also solved the blank line problem, using just vbLf.

Here is my actual code:

Private Sub PictureBox2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PictureBox2.Click

        Dim TextFile() As String
        Dim dir As String = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase)
        Dim FILE_NAME As String = (dir + "\\fernandopessoa.txt")
        Dim RandomNumber As Integer
        Dim RandomClass As New Random()
        Dim var As String
        If File.Exists(FILE_NAME) Then
            Dim objReader As New System.IO.StreamReader(FILE_NAME)
            Dim s As String = objReader.ReadToEnd
            Dim numero As String
            TextFile = s.Split(CChar(vbLf))
            numero = CStr((TextFile.Length - 1))
            RandomNumber = RandomClass.Next(0, CInt(numero))
            var = TextFile(RandomNumber)
            Label1.Text = var
            objReader.Close()
            objReader.Dispose()
        End If

As you can see in the code, i use random to pickup a array's content from the string and then i display it on the textbox.
However, i dont want array's content to be shown twice. This way i don't know how to start. I have several ideas and i would like you to point me in the best direction. I thought of one idea which was to add each random numbers to a list or something and then check if existed on the list. However i have never worked with lists and as far as i know me i would make a useless loop.
In theory (logical programing) i would program something like this:

A: Random x (from 0, to 40)-> If x exists on List, then GoTo A: Else add x to List.
If list content > 40 elements then msgbox "all done" - > Empty List and restart all.

Thanks and sorry.

[herpez]

By one or other way, the thread is solved.
Thanks to all!

[jmcilhinney]

The problem with splitting on just the LF is that the CR is left behind. You can't see it but it's there. That's why I suggested trimming.

As for unique random selections, follow the CodeBank link in my signature and check out my threads on the subject. They may need modification for the CF but you get the idea.

[herpez]

The problem with splitting on just the LF is that the CR is left behind. You can't see it but it's there. That's why I suggested trimming.

As for unique random selections, follow the CodeBank link in my signature and check out my threads on the subject. They may need modification for the CF but you get the idea.

Ok, thanks! I knew i didnt solve because otherwise you wouldnt say to trim. However, to my eyes it appeared to solve.
I will check codebank and threads.

Thanks